EFI conversion, need some direction...

[csouth]

I'm about to assemble my Olds 455 motor and the thought of doing and EFI conversion hit me. My intention id to probably run my carb to for a little while so i can a) learn the performance of my rebuild and b) properly plan my conversion considering both MPFI and TBI. I want to do a budget conversion(less than 1k), sort of a DIY with GM parts. My current mods are port matched heads and intake. Midrange came with optimal range of 1500-5500rpm and headers. Engine has been bored .030 over, but pistons are low compression 8:4:1
My questions are:
1) Can TBI support a BB motor and would this be a good option? I have access to a complete system from a 350 and a throttle from a Suburban w/454. The rest of the motor TBI was gutted(injectors, harness, ecu) I know thirdgen.org is a good source, but thought I would start here.

2) Could I grab parts from an LS1 (throttle, injectors, harness, sensors) and piece together a system. I know it will require modding my intake.

I've seen BigBlockOlds making progress on his EFI and I also read FuelFan's sticky. Just looking for a little advice to assist in my planning.:help!:

[mrn2obelvedere]

IMO you will be hard pressed to convert an engine for under 1K.

Technically speaking you could utilize the system from the 454. With the similar displacement it might work ok on things like cold start up and idle characteristics. The fuel curve might even be decently well suited as long as the motor is built very mildly. The problem I anticipate with running the 350 parts is that the fuel curves programmed into the controlling computer will be so far off from what your 455 will need. You will need to re flash the 350 computer (not sure about the details of this or even if this is possible) to get the fuel/timing stuff worked out.

I would suggest a DIY kit from megasquirt. You could utilize all of the hardware (throttle body, injectors, air temp, coolant temp, tps, fuel pump, etc) from basically any existing system, and control the parts with the fully programmable computer. I can't remember how much I paid for my megasquirt computer, but it was less than $300, and its really not hard at all to put together, and is very well documented with a lively online support community.

One of the biggest pains in my opinion in a conversion is setting up your fuel system to incorporate a fuel return. Once you have that worked out most of the other parts more or less bolt on with little modification.

Good luck!

[csouth]

I did think I would possibly get a Megasquirt ecu. I did see them unassembled for $200. That would probably be my highes price single item. I do know that the fuel pump fuel line is not cheap. We also have a few junk yards with LS1's where I could get the injectors and sensors, motors are not for sale because they are Cash for Clunkers cars. I have a guy that would be VERY reasonably priced to machine the bungs on my intake. On the TBI, i was aware that I would need a reprogram of the ECU. I would consider it a learning process using GM or a system with Megasquirt.

[The Stickman]

I am going down this road with my 350 SBO's. A complete ready built MegaSquirt plus wiring pigtail and computer hook up harness comes to just under $500. I have found a place to do my intake for under $300. That's welding on the bungs and drilling them out plus fitting the fuel rails. Taht's a pretty good deal if you ask me. Then I would need fuel lines from the tank and a fuel pump as well as sensors and wiring it up. I already have a 4 barrle style TB I bought off Ebay awhile back for under $200.

[csouth]

I am going down this road with my 350 SBO's. A complete ready built MegaSquirt plus wiring pigtail and computer hook up harness comes to just under $500. I have found a place to do my intake for under $300. That's welding on the bungs and drilling them out plus fitting the fuel rails. Taht's a pretty good deal if you ask me. Then I would need fuel lines from the tank and a fuel pump as well as sensors and wiring it up. I already have a 4 barrle style TB I bought off Ebay awhile back for under $200.

That was dirt cheap for a 4 barrel TB. My major expense would be the computer as I have a guy that does good machine work relatively cheap. Also considering Accel DFI. I know its pricey though

[The Stickman]

I just checked out the MegaSquirt site last night better and it seems amazingly simple. And for the price very cheap. The hard parts will be wiring it up and making it look nice and the fuel system. I will have to run all new lines and probably a new tank but I think I am lucky as an Impala/Caprice wagon tank should be a dirrect replacement.

[mrn2obelvedere]

The best thing about the Megasquirt is that you can really use just about anything as far as hardware is concerned. Whatever throttle bodies, injectors, fuel pumps, etc that you are running, in whatever combination, is fine.

You could use the 454 throttle body for a while but at some point you will need to consider an upgrade IMO unless you are keeping the 455 more or less stock. At some point the injectors in that throttle body won't be able to keep up. If you really wanted to do things on the cheap at that point you could just gut the TB (which would net you an increase in airflow) and machine the intake for injector bungs and basically run it as a multiport efi setup.

One thing I would caution you on though is that megasquirt really requires you to learn just about everything there is to know about efi. Also, the little things can really start to add up (sensors, fuel system, etc).